text: 
  exports.up = function(knex) {
      return knex.schema.table("question", (table) => {
          table.string('parentField', 255)
              .notNullable();
      });
  };
  
  exports.down = function(knex) {
      return knex.schema.table("question", (table) => {
          table.dropColumn('parentField');
      });
  };
  